Despite its proximity to the three major galactic powers of the Alpha-Beta Quadrant, as well as the smaller Thallonian Empire, the Expanse remained largely unexplored at least into the 2370s. The planet Azandria is less than half a light-year from the Expanse proper, obscured from long-range sensors by its effects. (Leto Colony) The USS Bozeman entered the Expanse in 2278 and did not return. Starfleet had presumed the Bozeman lost, but, in 2368, the vessel emerged from a temporal rift and collided with the USS Enterprise-D, destroying both ships and creating a temporal causality loop.